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Electron Density Shift in Imidazolium Derivatives upon Complexation with Cucurbit[6]uril
Author(s) -
Kolman Viktor,
Marek Radek,
Strelcova Zora,
Kulhanek Petr,
Necas Marek,
Svec Jan,
Sindelar Vladimir
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200900570
Subject(s) - substituent , supramolecular chemistry , chemistry , alkyl , molecule , electron density , spectral line , chemical shift , proton nmr , crystallography , nmr spectra database , stereochemistry , computational chemistry , organic chemistry , electron , physics , quantum mechanics , astronomy
In this study, we have investigated the supramolecular interaction between series of 1‐alkyl‐3‐methylimidazolium guests with variable alkyl substituent lengths and cucurbit[6]uril (CB6) in the solution and the solid state. Correct interpretation of 1 H NMR spectra was a key issue for determining the binding modes of the complexes in solution. Unusual chemical shifts of some protons in the 1 H NMR spectra were explained by the polarization of the imidazolium aromatic ring upon the complexation with the host. The formation of 1:1 complex between 1‐ethyl‐3‐methylimidazolium and CB6 is in disagreement with previously reported findings describing an inclusion of two guest molecules in the CB6 cavity.